Pile-supported Wharves Subjected to Combined Inertial and Lateral Ground Deformation Loads in Earthquakes

该奖项将提高海上运输系统在地震中的韧性，包括港口、码头和海军设施，这些设施是经济繁荣、应急响应和国家安全的关键组成部分。此外，港口通常是震后筹备和救灾工作的指定中心。然而，港口结构的抗震评估研究经常遇到与易液化的土壤-基础-结构相互作用有关的知识空白--地震时这种现象会导致土壤严重软化。对于在粉质土壤中支撑的基础(通常在港口设施中遇到)，知识差距变得更大，因为岩土工程界对于如何预测粉质土壤在地震中的行为没有达成共识。这项研究将通过进行一系列高级物理实验和数值模拟来解决这些知识差距。这项研究的结果将导致更安全、更具弹性的海上运输系统。与行业合作伙伴的密切合作将确保本研究中产生的知识将造福于更广泛的工程界。表征粉质土壤在地震中的行为将对评估和降低与美国太平洋西北部即将发生的9级卡斯卡迪亚俯冲带地震相关的风险产生重大影响，这将产生重大的经济和社会影响。这项研究还将得到与波特兰州立大学LSAMP项目的合作伙伴关系的补充，以帮助加强强调多样性的STEM教育。这项研究有两个具体的目标：(1)研究在长时间地震中，在多个循环荷载作用下，桩内塑性铰因增量屈服而产生的坍塌机理；(2)根据不同的地面运动特性、桩的性质、土体的剖面和土性，量化桩上的惯性和运动荷载的相互作用。这些目标将通过在加州大学戴维斯分校的自然灾害工程研究基础设施(NHERI)设施中进行一系列大规模土工离心机测试并结合数值参数模拟来实现。这项研究的结果将使人们深入了解可液化土壤中的桩上惯性和运动荷载的相互作用，这是新的和现有的港口以及其他桩支撑结构(包括公路桥、建筑物和近岸结构)的地震评估研究所必需的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award will improve the resilience of maritime transportation systems in earthquakes, including ports, terminals, and Navy facilities which are key components of economic prosperity, emergency response, and national security. In addition, ports are often designated centers for post-earthquake staging and relief efforts. However, seismic evaluation studies of port structures often encounter a knowledge gap related to soil-foundation-structure interaction in soils that are susceptible to liquefaction – a phenomenon that causes severe softening of soils in earthquakes. The knowledge gap becomes even wider for foundations that are supported in silty soils (commonly encountered at port facilities) as there is no consensus in the geotechnical community on how to predict the behavior of silty soils in earthquakes. This research will address these knowledge gaps by performing a series of advanced physical experiments and numerical simulations. The findings of this research will result in safer, more resilient maritime transportation systems. Close collaborations with industry partners will ensure that the knowledge produced in this study will benefit the broader engineering community. Characterizing the behavior of silty soils in earthquakes will have a significant effect in assessing, and reducing, the risks associated with an imminent Magnitude 9 Cascadia Subduction Zone earthquake in the Pacific Northwest of the U.S. with substantial economical and societal impacts. The research will also be complemented by a partnership with the LSAMP program at Portland State University to help enhance STEM education with emphasis on diversity. This research has two specific objectives: (1) to investigate a collapse mechanism due to incremental yielding in in-ground pile plastic hinges when subjected to many cycles of loading in long-duration earthquakes, and (2) to quantify the interaction of inertial and kinematic loads on piles with respect to various ground motion characteristics, pile properties, soil profiles, and soil properties. These objectives will be achieved by performing a series of large-scale geotechnical centrifuge tests at the Natural Hazards Engineering Research Infrastructure (NHERI) facility at UC Davis combined with numerical parametric simulations. The results of this research will provide an in-depth understanding of the interaction of inertial and kinematic loads on piles in liquefiable soils which are needed for seismic evaluation studies of new and existing ports as well as other pile-supported structures including highway bridges, buildings and nearshore structures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.